Hill holder device for a motor vehicle

ABSTRACT

The invention relates to a motor vehicle comprising at least one device for preventing unintentional movements.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motor vehicle as well as to a methodfor operating a motor vehicle.

2. Description of the Related Art

A method for operating a motor vehicle in a particular way, namely amethod to assist a motor vehicle starting operation, is already knownfrom DE 196 30 870 A1.

DE 196 30 870 A1 proposes to assist a starting operation of a motorvehicle having an automatic transmission and that is secured in a restcondition by brake engagement through an external force, to subsequentlydetect a torque produced by a drive motor. As soon as the torque exceedsa threshold value, brake engagement is released according to the knownmethod.

That known arrangement is suitable for assisting motor vehicle startingoperation in certain driving situations.

Of course, certain improvements with regard to flexibility as well asassembly possibilities of such an arrangement are desirable.

The object of the present invention is to provide a motor vehicle thatprevents unintentional rolling away in given conditions, and that at thesame time is economical as well as structurally simple to manufactureand that is additionally very versatile.

SUMMARY OF THE INVENTION

In accordance with the invention there is consequently provided a motorvehicle that has an electronically-controlled clutch apparatus and/orthat has an automated shift transmission and that is provided with ahill holder apparatus.

The hill holder apparatus prevents undesired movement of the motorvehicle primarily under predetermined conditions, that is, atpredetermined times or in predetermined situations.

The terms “undesired motion” as well as “brake effect” are in the senseof the invention to be understood to be broadly construed. The term“brake effect” applies, for example, according to intention, to aparking brake system and to parking brake system operation and/or aservice brake and to service brake operation. Likewise, any type ofdelayed engagement of starting movement can be understood by that term.

It should be noted that, in the sense of the invention, at leastindirect should be understood particularly to be direct and/or indirect.

The motor vehicle has a drive system such as, for example, an engine.Preferably the engine is an internal combustion engine. The motorvehicle is further provided with a driven system. The driven systemincludes for example at least one axle and at least two wheels.Preferably the driven system includes four wheels.

The motor vehicle in accordance with the invention further includes atorque transmitting apparatus such as a clutch, as well as atransmission unit.

The transmission unit is disposed between the drive system and thedriven system. Preferably, the torque transmitting apparatus is disposedbetween the transmission unit and the drive system. Especially preferredis the disposition of the transmission unit between the drive system andthe torque transmitting apparatus.

The invention is in that respect advantageous in that for motor vehicleswith electronically-controlled clutch arrangements (designated by theapplicant as electronic clutch management EKM) as well as ASG motorvehicles, undesired rolling away of the motor vehicle is prevented in asecure and reliable type and way. Those situations of undesired rollingaway can occur, for example, on a hill. Accordingly, a hill holderarrangement makes possible during starting, for example, retention of amotor vehicle immediately before, as well as during, the startingprocess. But a hill holder apparatus in accordance with the inventionalso makes possible the prevention of undesired motor vehicle movementbeyond one of such starting processes. Further, the invention isadvantageous to the extent that it can be very flexibly matched withspecific motor vehicles having ASG, as well as electronically controlledclutch arrangements.

In accordance with an especially preferred embodiment of the inventionundesired movements of a motor vehicle are terminated as well asprevented by the hill holder apparatus.

It is also preferred that the hill holder apparatus terminates as wellas prevents rolling away on a hill.

In accordance with an especially preferred embodiment of the invention,a braking as well as a parking operation can be performed on the vehicleby the hill holder apparatus at predetermined times and/or inpredetermined situations.

Preferably further, the hill holder produces direct and/or indirectcoupling in the manner of a clutch between at least a portion of thedrive system and at least a portion of the driven system. The clutch is,for example, designed in such a manner that components that are movablewith respect to each other during vehicle rolling motion are firmlycoupled to each other. For example, the invention provides that acomponent mounted in the torque flow between the drive system and thedriven system is at least temporarily rigidly affixed in place relativeto the vehicle body.

It is further preferred that the drive system and/or the driven systemare at least partly firmly affixed relative to the vehicle body, wherebythe drive system again is firmly coupled to the driven system.

According to an especially preferred embodiment of the invention, thehill holder apparatus engages essentially independently of the servicebrake in a vehicle movement situation.

It is further especially preferred that the hill holder apparatuscontrols the vehicle motion status at least in part and/or at leasttemporarily as a function of at least one vehicle condition parameter.Such a vehicle condition parameter for instance is its speed or theclutch temperature or a rotational speed, such as engine rpm or thetransmission rotational speed. It is also preferred that the movementcondition of the motor vehicle is controlled at least partly as afunction of its driving condition. For example, one such drivingcondition is “creeping” or “starting” or “driving” or “neutral” or“park.”

It is further preferred that the hill holder apparatus is at least inpart designed as a locking system or has at least part of a lockingsystem.

In accordance with another especially preferred embodiment of theinvention, the hill holder apparatus is at least partly mechanical, orengages at least partly an at least partly mechanical component.Especially preferred is a clutch based at least in part on mechanicalprinciples, which is controlled by the hill holder apparatus.

Especially preferred, further, the hill holder apparatus has at least aportion of a mechanical locking system or represents a part of amechanical locking system. A locking system based on other principlesalso is preferred in accordance with the invention.

An especially preferred motor vehicle has a hill holder apparatus withat least one free-wheeling component. The free-wheeling component ismounted, for example, near the transmission. For example, the operationof such a free-wheeling component can be controlled as a function ofrotational speed. Preferably, one direction of rotation is blocked insome ranges of rotational speeds. Preferably further, the free-wheelingcomponent operates in such manner that under certain situations onedirection of rotation is blocked. For example, the hill holder apparatusis designed with a free-wheeling component in such a manner thatwhenever the accelerator pedal is not operated, the free-wheelingcomponent is switched to prevent vehicle backward movement. It isfurther preferred that at least one free-wheeling component isassociated with the individual transmission gear ratios.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is at least partly electrical. It is furtherpreferred that the hill holder apparatus has at least a portion of anelectrical locking system.

Especially preferred, the hill holder apparatus is at least partlymagnetic. Also preferred is an at least partly electromagnetic hillholder apparatus.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is at least partly hydraulic. It is alsopreferred that the hill holder apparatus is at least partlyhydraulically driven. An especially preferred embodiment of a motorvehicle in accordance with the invention equipped with a hill holderapparatus has a connection possibility at least partially enclosed bythe hill holder apparatus, over which at least temporarily a positivelocking connection is produced to prevent as well as to limit motorvehicle movement. It is also preferred that a positive lockingconnection over the hill holder apparatus is at least temporarilyreleasable

In an especially preferred embodiment of a motor vehicle in accordancewith the invention with a hill holder apparatus, the hill holderapparatus is designed in such a manner that by means of it at leastpartially and/or at least temporarily a substantially positive-lockingconnection is produced and/or is releasable. It is also preferred thatat least partially and for at least temporarily a frictional connectionis produced by the hill holder apparatus and/or is releasable.

In an especially preferred motor vehicle in accordance with theinvention the positive and/or frictional connection set up by the hillholder apparatus is arranged at least partly in the torque path betweenthe drive system and the driven system.

It is further preferred that the clutch or the clutch operation isaffected or controlled at least in part by the hill holder apparatus. Inan especially preferred manner the clutch actuation apparatus is atleast partly actuated or affected or controlled by the hill holderapparatus.

In an especially preferred embodiment of the invention, the vehiclemotion may be affected or prevented by engaging an electronicallycontrolled clutch such as the applicant's marketed electronic clutchmanagement (EKM) device.

In this respect and in an especially preferred manner, the hill holderapparatus engages an electronically controlled clutch to suppress motorvehicle rolling. For instance, under predetermined conditions the hillholder apparatus will transmit a signal to the clutch actuationapparatus, whereby the clutch closes at least partly. Preferably in thisrespect, the clutch closes enough to prevent it from slipping.Preferably also in this respect, the clutch closes to such an extentthat a predefined slippage or slippage torque occurs or can occur at theclutch.

In an illustrative manner, the invention provides that when the engineis substantially shut off, the clutch closes at least partly.

It is also preferred that the hill holder apparatus directly and/orindirectly engages at least partly an automatic transmission (ASG) toprevent the motor vehicle from being set in motion or to affect orprevent or reduce motor vehicle motion.

In an especially preferred manner the hill holder apparatus engages atleast partly the brake apparatus, such as the service and/or parkingbrake of the motor vehicle. In an especially preferred manner, the brakeapparatus is at least partly automated.

It is further preferred that the hill holder apparatus is enclosed atleast partly by the brake actuation apparatus. It is also preferred thatthe hill holder apparatus is coupled at least partly and/or at leasttemporarily with the brake apparatus and/or the brake actuationapparatus.

An especially preferred motor vehicle in accordance with the inventionwith a hill holder apparatus has a direction-of-rolling detector todetermine the rolling direction of the motor vehicle and/or to determinea change in the rolling direction of the motor vehicle.

In an especially preferred manner, the motor vehicle in accordance withthe invention has a device for producing a signal that activates thehill holder apparatus. It is further preferred that the motor vehicle inaccordance with the invention has an apparatus which at predeterminedtimes will produce a signal to again deactivate the hill holderapparatus.

It is further preferred that the hill holder apparatus is, activatedunder predetermined conditions and is deactivated under predeterminedconditions.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is activated in such manner that a gearselector switch assumes a predetermined position and/or is put back in apredetermined way.

In another preferred embodiment, the hill holder apparatus is activatedwhen the transmission shift selector assumes the state “park.”Preferably, furthermore, the hill holder apparatus is activated when thetransmission shift selector assumes the state “park” and the motorvehicle speed is less than a predetermined limit speed.

In an especially preferred manner, the hill holder apparatus isactivated and/or deactivated as a function of motor vehicle speed and/orthe acceleration of the motor vehicle.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is activated or deactivated by the movementand/or driving condition of the motor vehicle.

It is also preferred that the hill holder apparatus is activated asneeded depending on the direction of rotation of at least one motorvehicle axle and/or at least one of its wheels. Preferably, the hillholder apparatus can be activated or deactivated for instance as afunction of the rotational speed of a drive wheel or of a drive axle ofthe motor vehicle. Preferably also, the hill holder apparatus can beactivated and/or deactivated as a function of rotational speed and/ormovement direction and/or change in rotational speed of at least onedriven wheel or one driven axle of the motor vehicle.

Preferably, further, the hill holder apparatus can be activated and/ordeactivated as a function of a change in direction of rotation of anaxle, such as a driving or a driven axle.

In accordance with an especially preferred embodiment of the inventionthe hill holder apparatus can be activated and/or deactivated at leastpartly depending on at least one signal from at least one sensor.Preferably, the hill holder apparatus is activated and/or deactivated asa function of a signal from a wheel rotation sensor and/or an enginespeed sensor.

In an especially preferred embodiment of the invention, the hill holderapparatus is activated and/or deactivated at least in part as a functionof the speed and/or the acceleration and/or the change in accelerationof the motor vehicle.

Preferably also, the hill holder apparatus is activated and/ordeactivated at least in part as a function of the position of anignition key and/or an ignition mechanism and/or as a function of achange in the position of an ignition key and/or an ignition mechanism.

Illustratively, the hill holder apparatus is activated when the vehiclespeed following removal of the ignition key drops below a predeterminedlimit speed.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is activated and/or deactivated at least inpart as a function of a measured or calculated temperature. For example,the hill holder apparatus is activated and/or deactivated as a functionof the clutch temperature.

It is also preferred that the hill holder apparatus is activated and/ordeactivated as a function of a distance covered by the motor vehicleand/or of a predetermined rotational speed of at least one tire.Preferably also, the hill holder apparatus is activated and/ordeactivated as a function of a predetermined time interval.

For example, the hill holder apparatus is activated when the motorvehicle is for instance in the mode “start” or “creep” longer than apredetermined pause period

It is especially preferred that the predetermined time interval beginsupon a predetermined event and/or at a predetermined time.

Preferably also, the hill holder apparatus is inactivated atpredetermined times and/or under predetermined conditions.

Preferably, further, the hill holder apparatus is inactivated as afunction of clutch-engagement intensity. Preferably, further, the hillholder apparatus is inactivated as a function of predeterminedconditions of the electronically controlled clutch and/or the ASG.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus is inactivated based on the course of thereference slope of a reference component of the clutch.

Preferably also, the hill holder apparatus can be inactivated as afunction of the position and/or the time progress of the position of afuel-measuring member such as the accelerator pedal.

In accordance with a preferred embodiment of the invention, the hillholder apparatus can be inactivated based on the vehicle's drivingconditions.

Preferably also, the hill holder apparatus can be inactivated based onpredetermined motor vehicle condition parameters or their magnitude ortheir change over time.

In accordance with an especially preferred embodiment of the invention,the hill holder apparatus can be inactivated as a function ofpredetermined shifting procedures and/or shift paths and/or shiftpositions of the transmission shift lever.

Preferably further, the hill holder apparatus can be activated and/ordeactivated or inactivated as a function of power loss, for instance thepower loss at the clutch.

In accordance with the invention there is also provided a method fordriving a motor vehicle equipped with an electronically controlledclutch and/or an automatic transmission (ASG), that, under predeterminedconditions, the motor vehicle [shall] is prevented from being set inmotion and/or rolling away. It is further preferred that underpredetermined conditions wherein motor vehicle motion is unwanted, themotor vehicle is stopped automatically, i.e., in an automated manner.

In accordance with an especially preferred embodiment of the invention,a check is first carried out whether the transmission shift selector isin “park.” As long as that condition is met, the next check is whetherthe vehicle speed is less than a predetermined speed. Preferably also,the vehicle speed is checked for being within a predetermined speedinterval. Especially preferred also is that parameters related todriving speed are checked to determine whether they are within apredetermined range and/or larger and/or smaller than a predeterminedlimit value.

So long as the motor vehicle speed is less than the predetermined limitspeed, then the above conditions or supplemental ones will apply andbraking or stopping the vehicle will then be initiated. Preferably also,a hill holder apparatus is activated.

In accordance with an especially preferred embodiment of the invention,a check is first carried out whether the vehicle is in a start mode. Ifthat is the case, a next check is made to ascertain whether the vehiclespeed is less than a predetermined limit speed. Alternatively and/oradditionally, the above checks can also be carried out. Provided thevehicle speed is less than the predetermined limit speed, i.e., that theother conditions be met additionally or equivalently, a check is carriedout whether the vehicle is in the start mode longer than a predeterminedlimit period and/or at less than the predetermined limit speed value.

Preferably also, a check is carried out, i.e., in complementing manner,whether the above conditions, such as whether vehicle speed is within apredetermined interval, are fulfilled.

The above limit period can be, for example, 60 seconds or 50 seconds or40 seconds or 30 seconds or 20 seconds or 15 seconds or 10 seconds or 8seconds or 6 seconds or 4 seconds or 2 seconds or 1 second.

If the vehicle remains in a given condition longer than thepredetermined time interval, the hill holder apparatus will subsequentlybe activated, i.e., the motor vehicle is transferred into a givenmovement condition. This movement condition is especially a movementcondition in which the motor vehicle is substantially at rest.Preferably also, the motor vehicle is transferred into a movementcondition in which the speed of the motor vehicle is less than apredetermined second speed.

The predetermined condition is determined, for example, or inparticular, by the vehicle being in a start mode and/or the speed of themotor vehicle being less than the predetermined (first) speed.

In accordance with an especially preferred embodiment of the invention,the first check is whether the vehicle is in a start mode.

If that is the case, whether the vehicle is rolling back is subsequentlychecked. That can be determined, for example, by means of the directionof rotation of at least one vehicle axle and/or at least one motorvehicle tire and/or at least one component of the transmission. Itshould be noted in this respect that the invention includes a number offurther possibilities. As long as the vehicle is rolling backward,whether motor vehicle speed is greater than a predetermined limit speedis subsequently checked.

So long as the motor vehicle speed is greater than the limit speed, thehill holder apparatus will be activated, i.e., the vehicle will beforced into a substantially movement-free condition.

It should be noted that here instead of sensing speed or limit speeds,parameters such as the rotational speed can also be used. By way ofexample, a rotational speed limit can be established.

It should also be noted that preferably the combined efforts of theindividual features in accordance with the invention can be used inevery arbitrary combination. In particular the combinations of featuresdisclosed in the independent claims of which one or more characteristicshave been omitted also are preferred.

It should be noted that the linkages of features expressed as “or”denote on one hand the mathematical “or” and on the other hand the “or”which excludes the other possibility.

It should further be noted that the concepts of control and theirderivative concepts are to be construed widely in the sense of theinvention. It also includes especially regulation and/or control in thesense of the DIN.

It will be apparent to those skilled in the art that from theherein-described embodiments of the invention numerous furthermodifications and embodiments are conceivable that are included withinthe invention. The invention is particularly not restricted to theembodiments described herein.

In the following, the invention will now be further explained on thebasis of an exemplary, non-restricting embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

There is shown:

FIG. 1 the steps of a first exemplary method in accordance with theinvention;

FIG. 2 the steps of a second exemplary method in accordance with theinvention;

FIG. 3 the steps of a third exemplary method in accordance with theinvention;

FIG. 4 a schematic representation of a motor vehicle that includes ahill holder in accordance with the invention, and

FIG. 5 another schematic representation of a motor vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the course of an exemplary first method in accordance withthe invention.

With it step 12 examines whether the transmission shift selector standsat “P” (=park). As long as that is the case, step 14 checks whether themotor vehicle speed is less than a first limit value for the vehiclespeed, limit value G1. As long as that is the case, the hill holder isactivated in step 16. That follows, by way of example, by closing of thebrake. By way of example a brake engagement follows. The possibilitiesavailable for that are, for example, brake-by-wire or automating theparking brake.

It should be noted that the vehicle speed can be determined from, forexample, rotational speed information that is made available, forexample, by the ABS sensors or by tachometer speed.

It should further be noted that the minimum value G1 is for example 3km/h. Further, it is preferred that the activation of the hill holder isequal to a locking of the service brake.

FIG. 2 shows a second exemplary course of a method in accordance withthe invention. Therein whether the motor vehicle is in a starting modeis checked in step 20.

So long as the motor vehicle is in a starting mode, the speed will bechecked (step 22). Thereby, whether the vehicle speed is less than apredetermined limit value, value G2, will be checked. The motor vehiclespeed can be determined from, for example, the rotational speedinformation. That information can be made available, for example, by theABS sensors. It is also preferred that it be obtained from thetachometer speed. The minimum value G2 for the vehicle speed amounts to,for example, 3 km/h. But other predetermined speeds such as, forexample, 10 km/h or 9 km/h or 8 km/h or 7 km/h or 6 km/h or 5 km/h or 4km/h or 2 km/h or 1 km/h also are [also] preferred.

As long as the vehicle speed is less than the limit value G2, there willsubsequently be a check in step 24 whether the aforesaid condition lastslonger than a predetermined time period, limit value G3. Thepredetermined time period G3 amounts to, for example, 20 or 15 or 12 or10 or 8 or 5 or 3 or 2 or 1 second(s).

As long as the condition lasts longer than the predetermined time periodG3, the hill holder will subsequently be activated.

It should be noted that instead of a time control, or supplementary to atime control, a control of a measured and/or a calculated temperature isalso possible such as, for example, clutch temperature.

By way of example, the hill holder can be activated when the clutchtemperature is above a predetermined clutch temperature G4. The clutchtemperature is preferably measured at a predetermined position.

By way of example, the limit value G4 for the clutch temperature is 300°C., whereby that 300° C. lies at a position 4 mm below the liningsurface of the clutch. It is also preferred that control of the powerloss in the clutch be considered. It is preferred, by way of example,that the hill holder is activated when a predetermined power loss islonger than a pre-defined time interval.

It is also preferred that the control be undertaken based upon the powerloss and/or the temperature instead of or supplementary to the timecontrol.

FIG. 3 shows a third exemplary course of a method in accordance with theinvention.

In accordance with that exemplary embodiment step 30 checks whether themotor vehicle is in a starting mode. As long as that is the case,subsequently in step 32 the rolling direction of the motor vehicle ischecked. Basically, each person skilled in that art will hereby knowstrategies that can be utilized to recognize whether a motor vehicle isrolling backward.

As long as backward rolling is determined, it will subsequently bechecked whether the speed of the motor vehicle is greater than apredetermined speed limit G5 (step 34).

As long as that is the case, the hill holder will be activated in step36. Thereby, for example, further motor vehicle movement will beprevented through a clutch engagement and/or other hill holderoperation.

It is also preferred that the engagement of the hill holder isassociated with further conditions. For example, the hill holder isengaged when the motor vehicle rolls back a predetermined distance. Asan example, the wheel circumference and the rotation can be used toascertain the distance (for example, one wheel revolution).

It is also preferred that the hill holder only engages when apredetermined backward rolling speed G5 exists, for example 3 km/h.Besides, it can be pointed out that the speed check, that is, the checkwhether the speed is greater than the value G5, can also be dispensedwith.

The invention furthermore provides an apparatus for an automatic clutchand/or an automatic transmission. Those devices have actuation units anda control unit, such as an electronic control unit with a computer unitand a data storage device.

In the hill holder arrangement there likewise exists an actuationarrangement that, for example, can be integrated into the control unitof an automatic clutch or the transmission control of an automatictransmission or a continuously variable transmission (CVT). In that way,if necessary, the structural space can be better utilized; and shorterpaths between control devices can be used. The likelihood of losses atinterfaces is thereby reduced.

Likewise, the electronic controls, with or without the power units forthe actuation units, can also be constructed in a separate control unit.That produces an advantageous condition when the structural spacesituation is such that two small sub-units are needed, in which thosecan be better accommodated in an indented structural space.

By way of example, a hill holder unit can be an automatically actuatedbrake.

That brake can be actuated, for example, in a situation where the motorvehicle is standing, the engine is off, and the clutch is disengaged, sothat the motor vehicle does not roll away in the case the ground is notlevel.

Likewise, it can be automatically actuated when during a motor startattempt the clutch is opened by means of an actuating element or thetransmission is in the neutral region. That leads to increased safety sothat during motor starting there exists no torque-transmittingconnection between the engine and the wheels, and therewith the hillholder unit can prevent rolling away. The automatically actuated brakecan also be operated to provide assistance during a starting process, inwhich during starting on a slope rolling in the opposite direction isavoided or reduced.

Moreover, it is appropriate for the hill holder to be actuated when, forinstance, it is necessary to be stationary for a procedure of theautomatic clutch such as, for instance, a calibration or adaptation of aquantity, such as the engagement point.

While controlling automatic clutches or automatic transmissions inaccordance with the invention, inclines in the roadway can be detectedwith the help of signals. While starting the motor vehicle on an inclinethe recognition can only be accomplished after a known time. In thatcase, when the foot or hand brake are not employed, that leads to ashort rearward rolling of the motor vehicle.

In motor vehicles in accordance with the invention with automaticparking brakes, that, for example, are actuated by a drive unit that canfor example be steplessly actuated, such as an electric motor, such aparking brake can be controlled in such a manner that starting of themotor vehicle only through the actuation of the accelerator follows andrearward rolling is avoided. That will be achieved, for example, thatthe motor vehicle brake, such as a parking brake or a service brake, isautomatically closed when the motor vehicle is standing without thetransmission gear being engaged. If the accelerator is thereafteractuated, and an increased drive power of the engine is set, the clutchwill be engaged to assure the starting procedure, and at the same timeor for a delay period the brake can be opened. In that connection, it isadvantageous for the torque to cause a forward thrust of the motorvehicle to be greater than the remaining slope drive-off momentum.

For the driving situation of starting a motor vehicle on an ascendingroadway, the control of the automatic clutch and the automatic brake(hill holder) recognizes that driving situation, for instance uponbackward rolling of the motor vehicle as a result of not actuating thefoot brake and correspondingly delayed actuation of the, acceleratorpedal. During the normal temporary displacement, by this ending of thefoot brake activation and the accelerator activation an insignificantrolling of the motor vehicle is at least possible. That can berecognized. This situation of the starting or standing on an incline canalso be assessed by a rapid activation of the foot brake on the part ofthe driver shortly after beginning a start. That follows then, forexample, when between the two brake activations there is an acceleratoractivation and a predetermined time threshold is not exceeded.

Furthermore, the existence of an incline of the roadway can beidentified, for example, when the actual place of the motor vehicle isidentified with a navigation system and to the actual position of themotor vehicle relative to the roadway profile a notation exists withregard to the incline/the descent. Consequently, whether a risingroadway or a descending roadway exists can be identified on the basis ofthe indication of information from a navigation system.

In a recognized situation of a present start up a hill, the parkingbrake can be controlled in such a way as to be tightly applied or closedso that a rearward movement of the motor vehicle is securely prevented,without, however, the clutch building up a transferable torque, by whichthe motor vehicle [is stopped] would be held on the hill by means ofclutch activation. By accelerator activation and correspondingcommencement of a starting procedure of a motor vehicle, the clutch willbe correspondingly so far open that the motor vehicle does not start tomove. When the transferable torque of the clutch becomes increasinglylarge, the parking brake will automatically be opened, so that from thesum of the driving force and the stopping force, against the downwardforce of the slope, the motor vehicle does not begin to roll.

FIG. 4 shows a motor vehicle 201 with a drive unit 202, such as aninternal combustion engine or a hybrid drive arrangement with aninternal combustion engine and an electric motor, with a torquetransmitting system such as clutch 203 and a transmission 204, whereinthe transmission has arranged behind it a drive shaft 205, which drivestwo drive shafts 207 a and 207 b by means of a differential 206, whichfurther drive the driven wheels 208 a and 208 b. The torque transmittingsystem constitutes a friction clutch 203 with a flywheel 209, a pressureplate 210, a clutch disk 211, a release bearing 212, and a clutch fork213, whereby the clutch fork is operated by means of an actuator 215with a master cylinder 216, a pressure communicator, such as a hydraulicconduit 217 and a slave cylinder 218. The actuator is represented as apressure-medium-actuated actuator, which has an electric motor 219 thatoperates the master cylinder piston 220 through a gear so that thepressure conduit 217 and the slave cylinder 218 can engage and disengagethe torque-transmitting system. Furthermore, the actuator 215 includesthe electronics for actuating and controlling the actuator, that is, thepower electronics as well as the control electronics. The actuator isprovided with a venting bore 221, which is connected with a reservoir222 for the pressure medium.

The motor vehicle 201 with the transmission 204 has a gear shift lever230 on which are arranged a gear recognition sensor 231 and a shiftintention sensor 232, which detects a shift intention of the driver onthe basis of movement of the shift lever, that is, on the basis of theapplied force. Furthermore, the motor vehicle is furnished with arotational speed sensor 233, which detects the rotational speed of thetransmission output shaft or the wheel rotational speed. Furthermore,there is provided a throttle valve sensor 234, which detects thethrottle valve position, and a rotational speed sensor 235, whichdetects the engine rotational speed.

The gear recognition sensor detects the position of internaltransmission shift elements or the gears in the transmission that areengaged, so that by means of the signal at least the applied gearposition is registered in a control unit. Furthermore, the movement ofthe internal transmission shift elements can be detected by an analogsensor, so that an early recognition of the next applied gear can beperformed.

The actuator 215 is powered by a battery 240. Moreover the apparatusprovides as a rule a multi-position ignition switch 241, which as a ruleis actuated by the ignition key, whereby the starter of the internalcombustion engine 202 is engaged over the conduit 242. A signal isfurther transmitted over the conductor 243 to the electronic unit of theactuator 215, after which the actuator is activated by, for example,switching on the ignition.

FIG. 4 shows the hill holder in block 250, which cooperates at leastwith a motor vehicle brake 251, and the latter is at least temporarilyautomatically operated. For that purpose hill holder 250 includes anelectronic control unit and brake 251 has an actuation unit. The hillholder 250 is in signal communication 252 with the control unit of theautomatic clutch.

FIG. 5 shows a schematic representation of a drive train of a motorvehicle with a drive unit 601, such as an internal combustion engine ora motor, a torque transmission system 602, such as, for example, afriction clutch, a dry friction clutch or a wet-running friction clutch,a transmission 603 as well as a differential 604, output shafts 605, andwheels 606 driven by the output shafts. Rotational speed sensors (notshown) can be arranged on the wheels 606 to detect the rotational speedof the wheels. The rotational speed sensors can also be part of otherfunctional electronic units, such as, for example, an anti-lock brakesystem (ABS). The drive unit 601 can also be arranged as a hybrid drivewith, for example, an electric motor, a free-wheeling flywheel, and aninternal combustion engine.

The torque transmission system 602 is arranged as a friction clutch,whereby the torque transmission system can also be arranged, forexample, as a magnetic particle coupling, a plate clutch, or a torqueconverter with a converter lockup clutch, or another clutch.Furthermore, FIG. 5 shows a control unit 607 and a schematically-shownactuator 608. The friction clutch can also be constructed as awear-regulated, self-adjusting clutch.

The torque transmission system 602 is mounted on a flywheel 602 a or isconnected with it, whereby the flywheel can be a divided flywheel with aprimary mass and a secondary mass, with a damper unit between theprimary mass and the secondary mass, and on which a starter ring gear602 b is arranged. The torque transmission system has collectively aclutch disk 602 c with friction linings and a pressure plate 602 d, aswell as a clutch cover 602 e and a plate spring 602 f. Theself-adjusting clutch has, in addition, means which allow regulation andwear adjustment, whereby a sensor, such as a force or direction sensoris present, which detects a situation in which an adjustment isnecessary and by which detection also is carried out.

The torque transmission system is operated by a disengagement device 609such as, for example, a pressure-medium-operated, such as hydraulic,central disengagement device, whereby the disengagement device can carrya release bearing 610, and by means of admission the clutch can beengaged and disengaged. The disengagement device can also be formed as amechanical disengagement device, which operates a release bearing or acomparable element, by impinging or by operation.

The actuator 608, as a working unit, controls the mechanical orhydraulic disengagement device or central disengagement device to engageor disengage the clutch over a mechanical connection or over a pressurecommunication 611 or a pressure transmission span, such as a hydraulicconduit. The actuator 608, with its at least one output element, or withseveral output elements, furthermore operates to shift the transmission,whereby, for example, a central selector shaft of the transmission isoperated through the output element or the output elements. The actuatortherewith operates internal transmission shift elements of thetransmission, such as a central selector shaft or shift rods or othershift elements, to engage, disengage, or change the gear stages ortransmission ratios.

The actuator 608 can also be arranged as or provided as a shift controlactuator, and which is arranged within the transmission. The shiftcontrol operates through a driving self-rotation in guiding guidedelements, such as shift elements, to shift the gear stages. Furthermore,the actuator for shifting the gear ratios can also contain the actuatorfor operating the torque transmission system, whereby in that case anoperating connection to the clutch release device is necessary.

The control unit 607 is connected with the actuator by the signal line612, so that control signals and/or sensor signals or operatingcondition signals can be exchanged, transmitted, or scanned.Furthermore, the signal connections 613 and 614 are available, overwhich the control unit can be in signal connection with further sensorsor electronic units, at least from time to time. Such other electronicunits can be, for example, engine electronics, anti-lock braking systemelectronics, or anti-skid system electronics. Further sensors can besensors that in general characterize or detect the operating conditionof the motor vehicle, such as, for example, rotational speed sensors ofthe engine or of the wheels, throttle plate position sensors,accelerator position sensors, or other sensors. The signal connection615 provides a connection with a data bus, such as, for example, a CANbus, over which system data concerning the motor vehicle or otherelectronic units can be provided to be available, because the electronicunits as a rule are linked together by computer units.

An automatic transmission can in that way be shifted or a gear changecan be practiced that is initiated by the driver of the motor vehicle,in which through, for example, a switch he gives a signal to upshift ordownshift. Furthermore, by means of an electronic shift lever a signalcan be provided to be available in which gear the transmission is to beshifted. By means of, for example, characteristic values, characteristiccurves, or characteristic fields and on the basis of sensor signals byknown, predetermined points an automatic transmission can also carry outa gear change independently, without the need for the driver to bringabout a gear change.

The motor vehicle is preferably equipped with an electronic acceleratorpedal 623 or load lever, whereby the accelerator pedal 623 triggers asensor 624 by means of which the engine electronics 620 controls orregulates, for example, the fuel supply, moment of ignition, injectiontime, or throttle-valve position over the signal conduit 621 of engine601. The electronic accelerator pedal 623 with sensor 624 is connectedover signal conduit 625 with the engine electronics 620. The engineelectronics 620 is connected over signal conduit 622 with the controlunit 607. Moreover, a transmission control electronics 630 can also beconnected with the units 607 and 620. A throttle-valve control having anelectric motor is appropriate therefor, whereby the position of thethrottle valve is controlled by the engine electronics. In such systemsa direct mechanical connection to the accelerator pedal is no longernecessary or appropriate.

For determining or calculating, for example, a transmission temperature,such as, for example, a transmission fluid temperature or a temperatureof a transmission element, the typical friction loss of transmissionparts and/or input rotational speed and/or output rotational speed ofthe transmission can be drawn upon. Furthermore, the fluid volumes andthe fluid flows can be taken into account. Moreover, otherabove-identified values can be taken into account in the calculation.The transmission temperature determination, however, must not be limitedto the slowing-down time; on the contrary, it can also be carried out inother operating situations.

The power applied to a control unit of an automatic transmission and/orof an automatic torque transmission system can be maintained, forexample, in order to carry on with specific operational functions aftervehicle operation, such as, for example, if, during temperaturedetermination or temperature calculation [for example] by means oftemperature models a critical condition is detected, such as, forexample, the clutch, the transmission, or the synchronization unit, orif for example adaptations are active or data are being ascertained orstored, such as, for example storing data or adapted values in anEEPROM. Further feasible adaptations of system values from an electricmotor, a transmission, or a pressure-medium system, such as a hydraulicsystem, can be carried out. Likewise, adjustments in the transmission orin the clutch (for example, during activation of a motor vehiclestopping unit) can be required or necessary to determine frictionalforces (sliding or static friction forces or friction values) andcharacteristic quantities for the actuator (for example motor parameterssuch as armature resistance or time constants for the electric motor).Furthermore, hydraulic values or other values, such as characteristiccurves of valves or other values can be balanced.

The invention relates to a motor vehicle with at least one hill holderunit to prevent undesired movement of the motor vehicle, whereby themotor vehicle has at least one electronically-controlled clutch unit tocontrol the clutch operation, and/or whereby the transmission apparatushas at least one automatic transmission, as well as a method foroperating a motor vehicle.

The claims included in the application are exemplary and are withoutprejudice to acquiring wider patent protection. The applicant reservesthe right to claim additional combinations of features disclosed in thespecification and/or drawings.

The references contained in the dependent claims point to furtherdevelopments of the object of the main claim by means of the features ofthe particular claim; they are not to be construed as renunciation toindependent, objective protection for the combinations of features ofthe related dependent claims.

Although the subject matter of the dependent claims can constituteseparate and independent inventions in the light of the state of the arton the priority date, the applicants reserve the right to make them thesubject of independent claims or separate statements.

The exemplary embodiments are not to be considered to be limitations ofthe invention. On the contrary, many changes and variations are possiblewithin the scope of the invention in the existing disclosure, inparticular such variants, elements, and combinations and/or materialswhich, for example, are inventive by combining or modifying singlefeatures that are in combination and are described individually inrelation to the general specification and embodiments as well as theclaims and shown in the drawings, as well as elements or method stepsthat can be derived by a person skilled in the art in the light of thedisclosed solutions of the problem, and which by means of combinedfeatures lead to a new object or new method steps or sequences of methodsteps, as well as manufacturing, testing and operational procedures.

What is claimed is:
 1. A method for preventing unintended rollingmovement of a motor vehicle, said method comprising the steps of: a.sensing whether a drive train of the vehicle is in anon-torque-transmitting mode whereby torque cannot be transmittedbetween an engine of the vehicle and at least one drive wheel of thevehicle to cause a transfer of power from the engine to the at least onedrive wheel, wherein the drive train includes a manually-shiftabletransmission and the drive train mode sensing step includes the step ofsensing whether the manually-shiftable transmission is in a neutralposition; b. sensing whether speed of movement of the vehicle is lessthan a predetermined limit speed value; c. engaging a vehicle brakingsystem to prevent rolling movement of the vehicle when the drive trainis in a non-torgue-transmitting mode and the speed of movement of thevehicle is less than the predetermined limit speed value.
 2. A method inaccordance with claim 1, wherein the drive train includes a clutch andthe drive train mode sensing step includes the step of sensing whetherthe clutch is in a disengaged position.
 3. A method in accordance withclaim 1, wherein the vehicle speed sensing step includes the step ofsensing a rotational speed within the vehicle drive train.
 4. A methodin accordance with claim 3, wherein the vehicle speed sensing stepincludes the step of sensing rotation of a vehicle driving wheel.
 5. Amethod in accordance with claim 3, wherein the vehicle speed sensingstep includes the step of sensing rotation of a transmission outputshaft.
 6. A method in accordance with claim 1, wherein the vehiclebraking system is a service brake system.
 7. A method for preventingunintended rolling movement of a motor vehicle, said method comprisingthe steps of: a. sensing whether a drive train of the vehicle is in anon-torque-transmitting mode whereby torque cannot be transmittedbetween an engine of the vehicle and at least one drive wheel of thevehicle to cause a transfer of power from the engine to the at least onedrive wheel, wherein the drive train includes an automatic transmissionand the drive train mode sensing step includes the step of sensingwhether the automatic transmission is in a park mode; b. sensing whetherspeed of movement of the vehicle is less than a predetermined limitspeed value; c. engaging a vehicle braking system to prevent rollingmovement of the vehicle when the drive train is in anon-torque-transmitting mode and the speed of movement of the vehicle isless than the predetermined limit speed value.
 8. A method in accordancewith claim 7, wherein the drive train mode sensing step includes thestep of sensing a transmission shift lever position.
 9. A method inaccordance with claim 7, wherein the vehicle speed sensing step includesthe step of sensing a rotational speed within the vehicle drive train.10. A method in accordance with claim 9, wherein the vehicle speedsensing step includes the step of sensing rotation of a vehicle drivingwheel.
 11. A method in accordance with claim 9, wherein the vehiclespeed sensing step includes the step of sensing rotation of atransmission output shaft.
 12. A method in accordance with claim 7,wherein the vehicle braking system is a parking brake system.
 13. Amethod in accordance with claim 7, wherein the vehicle braking system isa service brake system.
 14. A method in accordance with claim 7, whereinthe sensing step includes sensing whether the vehicle is in a startingmode, and the steps of determining whether the vehicle is in a startingmode longer than a predetermined limit time and wherein the step ofengaging the braking system is effected when the vehicle has been in thestarting mode longer than the predetermined time.
 15. A method inaccordance with claim 14, wherein the predetermined limit speed is 3km/h.
 16. A method in accordance with claim 14, wherein the vehiclespeed sensing step includes the step of sensing a rotational speedwithin the vehicle drive train.
 17. A method in accordance with claim14, wherein the vehicle speed sensing step includes the step of sensingrotation of a vehicle driving wheel.
 18. A method in accordance withclaim 14, wherein the vehicle speed sensing step includes the step ofsensing rotation of a transmission output shaft.
 19. A method inaccordance with claim 14, wherein the vehicle braking system is aparking brake system.
 20. A method in accordance with claim 14, whereinthe vehicle braking system is a service brake system.
 21. A method inaccordance with claim 14, including the steps of sensing a fuel supplymember position, and disengaging the engaged vehicle braking system whenthe fuel supply member position is greater than a predetermined fuelsupply member limit position.
 22. A method in accordance with claim 21,wherein the fuel supply member position is sensed by a throttle valvesensor.
 23. A method in accordance with claim 21, wherein the fuelsupply member position is sensed by an accelerator pedal positionsensor.
 24. A method in accordance with claim 7, including the step ofsensing a temperature associated with the vehicle, and wherein the stepof engaging the braking system is effected when the sensed temperatureis greater than a predetermined temperature.
 25. A method in accordancewith claim 24, wherein the temperature sensing step includes sensing thetemperature of a clutch positioned within a drive train of the vehicle.26. A method in accordance with claim 25, wherein the sensed temperatureis a clutch lining temperature.
 27. A method in accordance with claim26, wherein the predetermined temperature is greater than about 300° C.28. A method in accordance with claim 24, wherein the vehicle speedsensing step includes the step of sensing a rotational speed within thevehicle drive train.
 29. A method in accordance with claim 24, whereinthe vehicle speed sensing step includes the step of sensing rotation ofa vehicle driving wheel.
 30. A method in accordance with claim 24,wherein the vehicle speed sensing step includes the step of sensingrotation of a transmission output shaft.
 31. A method in accordance withclaim 24 , wherein the vehicle braking system is a parking brake system.32. A method in accordance with claim 24, wherein the vehicle brakingsystem is a service brake system.
 33. A method in accordance with claim24, including the steps of sensing a fuel supply member position, anddisengaging the engaged vehicle braking system when the fuel supplymember position is greater than a predetermined fuel supply member limitposition.
 34. A method in accordance with claim 33, wherein the fuelsupply member position is sensed by a throttle valve sensor.
 35. Amethod in accordance with claim 33, wherein the fuel supply memberposition is sensed by an accelerator pedal position sensor.
 36. A methodin accordance with claim 7, including the step of sensing whether themotor vehicle is moving in a backward direction; and wherein the step ofengaging the vehicle braking system is effected when the automatictransmission is not in a park mode and the vehicle is moving in abackward direction.
 37. A method in accordance with claim 36, includingthe step of sensing the vehicle backward movement speed, and engagingthe vehicle braking system when the motor vehicle is moving backward ata speed greater than a predetermined backward movement limit speed. 38.A method in accordance with claim 37, wherein the predetermined backwardmovement limit speed is about 3 km/h.
 39. A method in accordance withclaim 36, including the step of sensing vehicle backward movementdistance, and engaging the vehicle braking system when the motor vehiclehas moved backward a distance greater than a predetermined backwardmovement distance limit.
 40. A method in accordance with claim 37,wherein the vehicle speed sensing step includes the step of sensing arotational speed within the vehicle drive train.
 41. A method inaccordance with claim 37, wherein the vehicle speed sensing stepincludes the step of sensing rotation of a vehicle driving wheel.
 42. Amethod in accordance with claim 37, wherein the vehicle speed sensingstep includes the step of sensing rotation of a transmission outputshaft.
 43. A method in accordance with claim 36, wherein the vehiclebraking system is a parking brake system.
 44. A method in accordancewith claim 36, wherein the vehicle braking system is a service brakesystem.
 45. A method in accordance with claim 36, including the steps ofsensing a fuel supply member position, and disengaging the engagedvehicle braking system when the fuel supply member position is greaterthan a predetermined fuel supply member limit position.
 46. A method inaccordance with claim 45, wherein the fuel supply member position issensed by a throttle valve sensor.
 47. A method in accordance with claim45, wherein the fuel supply member position is sensed by an acceleratorpedal position sensor.
 48. A method for preventing unintended rollingmovement of a motor vehicle, said method comprising the steps of: a.sensing whether a drive train of the vehicle is in anon-torque-transmitting mode whereby torque cannot be transmittedbetween an engine of the vehicle and at least one drive wheel of thevehicle to cause a transfer of power from the engine to the at least onedrive wheel; b. sensing whether speed of movement of the vehicle is lessthan a predetermined limit speed value; c. engaging a vehicle brakingsystem to prevent rolling movement of the vehicle when the drive trainis in a non-torque-transmitting mode and the speed of movement of thevehicle is less than the predetermined limit speed value, wherein thevehicle braking system is a parking brake system.
 49. Apparatus forpreventing unintended rolling movement of a motor vehicle that includesa drive train for selectively interconnecting an engine with at leastone drive wheel, said apparatus comprising: a. a sensor for sensingwhether the drive train is in a non-torque-transmitting mode wherebytorque cannot be transmitted between the engine and the at least onedrive wheel to cause a transfer of power from the engine to the at leastone drive wheel, wherein the drive train includes a manually-shiftabletransmission and means sensing whether the manually-shiftabletransmission is in a neutral position; b. a sensor for sensing whetherthe vehicle is moving at a speed that is less than a predetermined limitspeed value; c. a control system responsive to signals from the vehicledrive train sensor and the vehicle speed sensor for engaging a vehiclebraking system to prevent rolling movement of the vehicle when the drivetrain is in a non-torque-transmitting mode and the speed of movement ofthe vehicle is less than the predetermined limit speed value. 50.Apparatus in accordance with claim 49, wherein the drive train includesa clutch and means for sensing whether the clutch is in a disengagedposition.
 51. Apparatus in accordance with claim 49, including vehiclespeed sensing means for sensing a rotational speed within the vehicledrive train.
 52. Apparatus in accordance with claim 51, wherein thevehicle speed sensing means senses rotation of a vehicle driving wheel.53. Apparatus in accordance with claim 51, wherein the vehicle speedsensing means senses rotation of a transmission output shaft. 54.Apparatus in accordance with claim 49, wherein the vehicle brakingsystem is a parking brake system.
 55. Apparatus in accordance with claim49, wherein the vehicle braking system is a service brake system.
 56. Amethod in accordance with claim 1, wherein the sensing step includessensing whether the vehicle is in a starting mode, and the steps ofdetermining whether the vehicle is in a starting mode longer than apredetermined limit time and wherein the step of engaging the brakingsystem is effected when the vehicle has been in the starting mode longerthan the predetermined time.
 57. A method in accordance with claim 56,wherein the predetermined limit speed is 3 km/h.
 58. A method inaccordance with claim 56, wherein the vehicle speed sensing stepincludes the step of sensing a rotational speed within the vehicle drivetrain.
 59. A method in accordance with claim 56, wherein the vehiclespeed sensing step includes the step of sensing rotation of a vehicledriving wheel.
 60. A method in accordance with claim 56, wherein thevehicle speed sensing step includes the step of sensing rotation of atransmission output shaft.
 61. A method in accordance with claim 56,wherein the vehicle braking system is a parking brake system.
 62. Amethod in accordance with claim 56, wherein the vehicle braking systemis a service brake system.
 63. A method in accordance with claim 56,including the steps of sensing a fuel supply member position, anddisengaging the engaged vehicle braking system when the fuel supplymember position is greater than a predetermined fuel supply member limitposition.
 64. A method in accordance with claim 63, wherein the fuelsupply member position is sensed by a throttle valve sensor.
 65. Amethod in accordance with claim 63, wherein the fuel supply memberposition is sensed by an accelerator pedal position sensor.
 66. A methodin accordance with claim 1, including the step of sensing a temperatureassociated with the vehicle, and wherein the step of engaging thebraking system is effected when the sensed temperature is greater than apredetermined temperature.
 67. A method in accordance with claim 66,wherein the temperature sensing step includes sensing the temperature ofa clutch positioned within a drive train of the vehicle.
 68. A method inaccordance with claim 67, wherein the sensed temperature is a clutchlining temperature.
 69. A method in accordance with claim 68, whereinthe predetermined temperature is greater than about 300° C.
 70. A methodin accordance with claim 66, wherein the vehicle speed sensing stepincludes the step of sensing a rotational speed within the vehicle drivetrain.
 71. A method in accordance with claim 66, wherein the vehiclespeed sensing step includes the step of sensing rotation of a vehicledriving wheel.
 72. A method in accordance with claim 66, wherein thevehicle speed sensing step includes the step of sensing rotation of atransmission output shaft.
 73. A method in accordance with claim 66,wherein the vehicle braking system is a parking brake system.
 74. Amethod in accordance with claim 66, wherein the vehicle braking systemis a service brake system.
 75. A method in accordance with claim 66,including the steps of sensing a fuel supply member position, anddisengaging the engaged vehicle braking system when the fuel supplymember position is greater than a predetermined fuel supply member limitposition.
 76. A method in accordance with claim 75, wherein the fuelsupply member position is sensed by a throttle valve sensor.
 77. Amethod in accordance with claim 75, wherein the fuel supply memberposition is sensed by an accelerator pedal position sensor.
 78. A methodin accordance with claim 1, including the step of sensing whether themotor vehicle is moving in a backward direction; and engaging thevehicle braking system to prevent rolling movement of the vehicle whenthe motor vehicle is in a starting mode and the vehicle is moving in abackward direction.
 79. A method in accordance with claim 78, includingthe step of sensing the vehicle backward movement speed, and engagingthe vehicle braking system when the motor vehicle is in a starting modeand is moving backward at a speed greater than a predetermined backwardmovement limit speed.
 80. A method in accordance with claim 79, whereinthe predetermined backward movement limit speed is about 3 km/h.
 81. Amethod in accordance with claim 78, including the step of sensingvehicle backward movement distance, and engaging the vehicle brakingsystem when the motor vehicle has moved backward a distance greater thana predetermined backward movement distance limit.
 82. A method inaccordance with claim 78, wherein the vehicle speed sensing stepincludes the step of sensing a rotational speed within the vehicle drivetrain.
 83. A method in accordance with claim 78, wherein the vehiclespeed sensing step includes the step of sensing rotation of a vehicledriving wheel.
 84. A method in accordance with claim 78, wherein thevehicle speed sensing step includes the step of sensing rotation of atransmission output shaft.
 85. A method in accordance with claim 76,wherein the vehicle braking system is a parking brake system.
 86. Amethod in accordance with claim 76, wherein the vehicle braking systemis a service brake system.
 87. A method in accordance with claim 76,including the steps of sensing a fuel supply member position, anddisengaging the engaged vehicle braking system when the fuel supplymember position is greater than a predetermined fuel supply member limitposition.
 88. A method in accordance with claim 87, wherein the fuelsupply member position is sensed by a throttle valve sensor.
 89. Amethod in accordance with claim 87, wherein the fuel supply memberposition is sensed by an accelerator pedal position sensor. 90.Apparatus for preventing unintended rolling movement of a motor vehiclethat includes a drive train for selectively interconnecting an enginewith at least one drive wheel, said apparatus comprising: a. a sensorfor sensing whether the vehicle is in a starting mode; b. a sensor forsensing whether the vehicle is moving at a speed lower than apredetermined limit speed; c. a timer for determining whether thevehicle is in the starting mode longer than a predetermined limit time;d. a control system responsive to signals from the vehicle starting modesensor and the vehicle speed sensor and the starting mode timer forengaging a vehicle braking system to prevent rolling movement of thevehicle when the vehicle is in a starting mode for a time greater thanthe predetermined starting mode limit time and the speed of movement ofthe vehicle is less than the predetermined limit speed value; and e.wherein the drive train includes a manually-shiftable transmission andmeans sensing whether the manually-shiftable transmission is in aneutral position.
 91. Apparatus for preventing unintended rollingmovement of a motor vehicle that includes a drive train for selectivelyinterconnecting an engine with at least one drive wheel, said apparatuscomprising: a. a sensor for sensing whether the motor vehicle is in astarting mode; b. a sensor for sensing whether the motor vehicle ismoving in a backward direction; c. a control system responsive tosignals from the vehicle starting mode sensor and the vehicle backwardmovement direction sensor for engaging a vehicle braking system toprevent rolling movement of the vehicle when the vehicle is in thestarting mode and is moving in a backward direction, and e. wherein thedrive train includes a manually-shiftable transmission and means sensingwhether the manually-shiftable transmission is in a neutral position.92. Apparatus for preventing unintended rolling movement of a motorvehicle that includes a drive train for selectively interconnecting anengine with at least one drive wheel, said apparatus comprising: a. asensor for sensing whether the drive train is in anon-torque-transmitting mode whereby torque cannot be transmittedbetween the engine and the at least one drive wheel to cause a transferof power from the engine to the at least one drive wheel, wherein thedrive train includes an automatic transmission and means sensing whetherthe automatic transmission is in a park mode; b. a sensor for sensingwhether the vehicle is moving at a speed that is less than apredetermined limit speed value; c. a control system responsive tosignals from the vehicle drive train sensor and the vehicle speed sensorfor engaging a vehicle braking system to prevent rolling movement of thevehicle when the drive train is in a non-torque-transmitting mode andthe speed of movement of the vehicle is less than the predeterminedlimit speed value.